This would require new animations which I can't do

You mean the movement of chair and sims together?
That will be hard...but if you manage to link the chair and sim to a animation file i can give it a try....
they prolly have to move individually or only the chair with a sim snapped onto.
The animation of the chair aint that hard, should be possible to even rotate the wheels.
If a sim normally walks, wich animation file is used then?
Its prolly a animation file on 2 or 3 tiles, noting more.
O well...